This invention relates to a control device for a door closer which is provided with a body part and the operation thereof being controlled by a pressure medium.
In a known type of door closer utilizing a pressure medium, a piston means displaces the pressure medium from one chamber to another through different flow channels according to the movement of the door or other wing member. By restricting and, when necessary, by controlling the flows through the flow channels, the opening speed and the closing speed of the door may be influenced during the different stages of the opening and closing movements. Besides speaking of controlling e.g. the starting speed and end speed of the normal closing movement, the terms opening brake, by which the door is prevented from being grabbed by the wind during the opening movement, particularly when the door is open for instance more than 60.degree., and closing retarder, by which correspondingly the closing of the door can be slowed down at the beginning stage of the closing movement to facilitate passing through, are used. Potentially, a door closer may include a separate control device for each flow channel.
In order to control the flow rate of the pressure medium a control device is conventionally used, wherein a control member is attached to a screw or the like for mounting the device in the door closer and for providing control. The control member is formed according to the respective need for control of the flow, placement (the particular flow channel to be controlled) and corresponding criteria. Traditionally the control device is made in one part, whereby for each purpose and placement a separate control device is provided, by which control can with advantage be accomplished. A problem with this solution is the requirement of high accuracy in manufacture, because even a slight axial eccentricity of the control member and the screw member may result in the control surface of the control member being damaged as the control device is turned. Furthermore, even a small change in the structure of the door closer may require redesigning of the control member of the control device and, thus, replacement of the whole control device with a new one.
Also known are control device solutions which are based on a screw member, which is turnable from outside of the door closer with a tool, and on a separate control member influencing the flow of pressure medium. A solution of this kind is disclosed in patent publication AT 219450, according to which a separate control member is pressed against a screw member by means of a spring. Thus, in this case the control device comprises two separate parts, which are not attached to each other as one unit before mounting into the door closer, but they are only pressed against each other by the spring when the control device is mounted ready for use in the door closer. The solution is complicated and functionally uncertain and the mounting and handling thereof are quite difficult.